1. Field of the Invention
The present invention relates to an electrically operated drawing system and, more particularly, to an electrically operated system for drawing curtains.
While the specification hereinafter generally relates to the drawing and undrawing of curtains, it is noted that the present invention is equally applicable to the drawing and undrawing of shades, drapes, covers, screens, blinds, accordion doors, and other types of barriers.
2. Statement of the Prior Art
The present inventor has previously proposed an electrically operated system for drawing curtains in Japanese Utility Model application No. 60-140669, now published as Japanese Laid-open application No. 62-51990. This application relates to an electrically operated drawing system designed to digitally detect an "off" signal at the time of completion of either the drawing or undrawing of a curtain to improve the responsiveness of the system, whereby both the inflow of surge currents into a logic circuit and the generation of noise are prevented, and whereby the malfunctions caused by external surge currents are avoided, thus resulting in improved reliability. However, that drawing system could not be changed over to a manual mode due to the absence of a clutch. In order to effect such a change-over to a manual mode, a clutch is required. Even with a device having an inexpensive mechanical clutch with a built-in solenoid, however, it is not possible to instantaneously effect a change-over of the operational mode due to the inertia of the solenoid mover.
The present inventor has also previously proposed an electrically operated system for drawing curtains in Japanese Utility Model application No. 61-89336, now published as Japanese Laid-open application No. 62-200982. This application relates to an electrically operated curtain drawing system which allowed for easy undrawing and drawing of a curtain whether in an electrically operational mode or in a manual mode and which was applicable to double curtains. In that electrically operated curtain drawer system, however, satisfactory gear-to-gear meshing was not always achieved and a jumping-over of the gears during operation was possible.